Diaphragm



March 1954 M. VAN DER PYL DIAPHRAGM Filed Dec. 4, 1950 INVENTOR LYMAN M. VAN DER Pw.

BY M

ATTORNEYS Patented Mar. 16, 1954 UNITED STATES PATENT OFFICE DIAPHRAGM Lyman M. Van Der Pyl, Penn Hills, Pa., assignor to Rockwell Manufacturing Company, Pittsburgh, Pa., a corporation of Pennsylvania Application December 4, 1950, Serial No. 199,059

1 Claim. (Cl. 73279) States Patent No. 1,966,985, issued July 17, 1934 r to G. B. Linderman, Jr. In such meters, the diaphragm assemblies each comprise a leather bellows secured at each end to rings by cording in the usual manner. The bellows of these assemblies are generally formed of one or more sheets of tanned lamb skin or imported goat skin, which has beentreated to prevent gas leakage through but these have proved unsatisfactory for various reasons. One example for such prior attempts is that disclosed in United States Patent No. 1,597,237, issued August 24, 1926 to F. McDonald. In bellows such as that of the McDonald patent, the adjacent edge portions are overlapped to form a lap joint, the flesh surfaces of the adjacent edge portions being in surface contact. The overlapped edge portions are secured together by a pair of blind edge seams, one formed from each side of the lap joint, and by a thin layer of adhesive cement between the flesh surfaces. While such a joint may be satisfactory in preventing leakage, ,it is quite limited in utility because it is not applicable to either a bellows made of a single piece, as is frequently done, or one made of any odd number of pieces, and because the reversal of alternate pieces results in non-uniformity of fiexure of the leather around such a bellows.

As is pointed out in the McDonald specification, this manner of securing overlapping edge portions by edge seams made from opposite sides of the joint has also been used to join pieces with the flesh side of one piece in surface contact with the hair side of the other, as is necessary if the bellows is made of a single or any odd number of pieces of leather. In such a joint, the hair side of both pieces is of necessity pierced by one of the edge seams. To prevent leakage through the relatively porous flesh side and through the scam, the threads of which pierce 2 the hair side of both edge portions, it is customary to apply cement both between the contacting surfaces and to the exposed pierced hair side along the seam and force it into the pores and along the threads by a vacuum applied to the back of the seam. This procedure necessarily increases the cost of manufacture of the bellows.

It is accordingly a primary object of this invention to provide an improved bellows for a diaphragm in which the edges of the leather are secured together in a novel manner which overcomes the foregoing disadvantages and limita tions of the prior art.

It is an object of this invention to provide a novel means for securing together adjacent edge portions of leather sheets to form bellows of a single or of any reasonable number of pieces of leather and which may be made leak proof more readily than those of the prior art.

It is an equally important object of this invention to provide a novel method of securing adjacent pieces of leather together in a lap joint in which the hair sideof one piece is not pierced by any seam.

It is a more specific object of this invention to provide a novel leather joint in which the hair side of one of the joined edge portions is not pierced by the seams of the joint and a novel method of producing such a joint.

These and other objects of this invention will become apparent as the detailed description proceeds in reference to the accompanying drawings wherein:

Figure 1 is a perspective view of a diaphragm assembly for a gas meter;

. Figure 2 is an enlarged perspective view of the joint at which adjacent edge portions of leather are secured; and

Figure 3 is a sectional View of the joint taken along the line 3--3 of Figure 2.

In Figural, one'type of diaphragm assembly of generally conventional design to which the present invention is applicable is shown. This diaphragm assembly comprises a leather bellows Ill which is secured at each end to rings l2 and 14 by cording H5 in the conventional manner. The leather joint of the present invention is not limited to a bellows formed of any particular number of sheets, but for simplicity, bellows H1 is disclosed as formed of a single sheet of leather, the hair side of which is external of the bellows and in which its opposite edge portions l 8 and 20 are overlapped to form a lap joint secured together by a pair of seams generally designated as 22 and 24.

The manner in which edges l8 and 20 are secured together is more clearly shown in Figures 2 and 3, wherein numerals 26 and 38 designate the outer surfaces of the flesh or relatively open porous sides of edge portions 20 and [8 respectively, while numerals 28 and 32 designate the outer surfaces of the hair or relatively pressuretight grain sides of these edge portions respectively. The hair side 28 of edge portion 20 is in contact with the flesh side 36 of edge portion I8 as shown.

A thin layer of adhesive cement such as nitrocellulose in solution in a suitable solvent is wiped over the edge 33 and one or both of the contacting surfaces prior to placing them in overlapping relationship for sewing. Cement is applied to edge 33 to prevent leakage of gas along the threads of the seams through the porous flesh side of edge portion i8 and the edge 33.

Seam 24 is formed of a pair of threads 34 and. 35 having loops interlocking within the leather, thread 34 lying along the exposed surface 26 of edge portion 2&3 and thread 3% lying along the flesh side 36 of edge portion 13 adjacent edge 38. The loops 35 of thread 34 extend into edge portion 26 while the loops 3! of thread 36 follow a curved path through the flesh side of edge portion [8, passing through surface 38 twice, and extending through surface 28 to interlock at 33 within the body of edge portion 22! with the loops of thread34 as is bestillustrated in Figure 3.

Seam 22 is similarly formed of a pair of threads 40 and 44 having loops 43 and 45 respectively interlocked at 47 within the body of edge portion 20, differing only in that both threads lie along the exposed surface 26 of edge portion 23. It should be noted that the point at which the threads interlock within the leather edge portions is not critical, being dependent upon the manner in which the seams are .formed.

Thus when the edges are joined by seams according to this invention, the relatively impervious hair side of the outer edge portion l 8 is not pierced at all so that no paths are formed by stitching along which gas may leak.

The preferred manner of forming this leakage resistant joint will now be described. Adhesive cement is applied to the flrst of the two edge portions to be joined, either to the flesh side of this edge portion or to the hair side of the second edge portion or to both. These two edge portions are then placed in overlapping relationship so that the flesh side of the first is in surface contact with the hair side of the second. A plurality of blind seams formed from the flesh side of the second edge portion, which pass through the relatively porous flesh side of the first edge portion without piercing the impervious hair side thereof, are then made to complete the joint.

Accordingly, the present invention contemplates an improved bellows for a diaphragm having an improved leakage resistant joint for the edges of diaphragm leather and an improved method of joining edges of leather to form such a leakage resistant lap joint. This invention constitutes an improvement over the prior art in that diaphragms can be formed of any number of pieces, odd or even, in that the pieces of leather may be arranged with the hair side of all pieces on one surface of the bellows for uniform flexure and in that the cost of manufacturing diaphragm bellows having leakage resistant leather joints is greatly reduced. There is no perforation of the hair sides of one of the overlapped edge portions.

While this embodiment of my invention has been described in detail for clarity, my invention may be embodied in other forms without departing from the spirit or essential characteristics thereof. The present invention is therefore intended to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claim rather than by the foregoing description, and all changes which come within the meaningv and range of equivalency of the claim are therefore intendedto be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

In a gas meter, a leather diaphragm of generally annular oonflguration having a continuous gas impervious barrier layer, said impervious layer being formed by the hair side of at least one discontinuous sheet of diaphragm leather and a gas impervious seal at each discontinuity in the hair side of the diaphragm leather sheet, each discontinuity in the diaphragm leather sheet be ing in the form of a lap joint in which the hair side of one leather end portion is cemented to the flesh side of an opposed leatherend portion, said gas impervious seal at each such discontinuity in the hair side of the diaphragm leather being formed by a layer of cement along the leather edge disposed on the hair side of the diaphragm at each such lap joint and the lap joint being reinforced by a plurality of seams of blind stitches, each seam being formed from the flesh side of said diaphragm leather whereby a strong joint is established while said barrier layer is maintained imperforate.

LYMAN M. VAN DER PYL.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,069,097 Bailey Aug. 5, 1913 1,206,365 Payne Nov. 28, 1915 1,597,237 McDonald Aug. 24, 1926 1,966,985 Linderman, Jr. July 17, 1934 

